The present invention relates to compressed air power plants and more specifically, to construction of a highly efficient engine powered by compressed air. It further relates to a means of converting a standard internal combustion engine into an efficient compressed air power generating system.
There exists several designs for pneumatic or compressed air motors. For example, U.S. Pat. No. 3,925,984 to Holleyman discloses a compressed air power plant for a vehicle which includes a low pressure air tank maintained by a low pressure compressor driven by an electric motor and battery and a high pressure tank maintained by a high pressure pump driven by a motor. Air from the high pressure tank is fed to a converted internal combustion engine through a solenoid operated valving system. The low pressure exhaust air expelled from the cylinders is exhausted into an exhaust tank, where air from the exhaust tank and air from the low pressure tank are directed by pumps into the high pressure tank. Holleyman therefore apparently discloses a compressed air power plant in which high compressed air is directed to the power plant at a single pressure level from a single output source.
U.S. Pat. No. 3,885,387 to Simington relates to an apparatus for modifying an internal combustion engine to operate as a compressed non-combustible gas engine. The reference discloses a compressed air tank and a valve for distributing air to the various cylinders through the spark plug ports. Simington also teaches the use of a single input of air at a single pressure to the cylinders of an engine providing power.
Other patents disclosing compressed air engines include U.S. Pat. Nos. 4,124,978 to Waggoner; 4,210,062 to Plesko; 4,018,050 to Murphy; 4,102,130 to Stricklin; 4,380,904 to Zappia.
While the above references appear to disclose air operated devices, it is believed that the efficiency provided by such devices may be exceeded by a compressed air power plant having a two stage system for supplying compressed air to the cylinders as described in greater detail below.